Negative pressure wound therapy (NPWT) is also known as vacuum assisted closure therapy or Wound VAC. Negative pressure wound therapy is type of therapy in which suction is used to draw fluids and drain away from an open wound. A special type of dressing is used to create the vacuum environment at the site of wound that increases the blood flow and also keeps the area clean. This will help to prevent and heal the infection. The devices for the negative pressure wound therapy are mechanical or powered (electrical).